Specifications

mpls ldp advertise-labels old-style
MP-203
Cisco IOS Multiprotocol Label Switching Command Reference
January 2010
Usage Guidelines The method for interpreting the for prefix-access-list parameter in the mpls ldp advertise-labels
command is defined by Rule 2.a in the “Usage Guidelines” section in the mpls ldp advertise-labels
command. This Rule 2.a follows normal access list conventions.
However, earlier Cisco IOS software versions used a different method for interpreting the fo
r
prefix-access-list parameter in mpls ldp advertise-labels command. For those earlier software versions,
Rule 2.a read as follows:
2.
A given prefix can have, at most, one (prefix acl, peer acl) pair that “applies” to it.
a. A given (prefix acl, peer acl) pair “applies” to a prefix only if the prefix acl “matches” the
prefix. A match occurs if the prefix acl explicitly permits or denies the prefix by means of a
permit or deny command. A prefix acl that contains a permit any or deny any command
matches any prefix.
This earlier Rule 2.a departed from normal access list conventions in that:
• An explicit deny (including a deny any) that matches the prefix causes the (prefix acl, peer acl) pair
to apply to the prefix.
• Explicit deny any and implicit deny any (which all access lists have) have different effects, in that
the explicit deny any causes the access list pair to apply to all prefixes, but the implicit deny any
has no effect.
Use the mpls ldp
advertise-labels old-style command to force the use of the old-style method of
interpreting the for prefix-access-list parameter used by earlier software versions if the following apply:
• A configuration developed for use with earlier software versions depends on this previous method
for interpreting the for prefix-access-list parameter in mpls ldp advertise-labels commands.
• It is inconvenient to update the configuration to work with Rule 2.a as it appears under the “Usage
Guidelines” section of the mpls ldp advertise-labels command.
Examples The following command causes the old-style method of interpreting the fo
r prefix-access-list parameter
to be used in executing mpls ldp advertise-labels commands:
Router# mpls ldp advertise-labels old-style
In the following example, the vrf keyword is specified to configure label advertisement in the VFR
instance named vpn1:
Router(config)# mpls ldp advertise-labels vrf vpn1 old-style
Related Commands Command Description
mpls ldp
a
dvertise-labels
Controls the distribution of locally assigned labels by means of LDP.